The field of the present invention is apparatus for the mounting of sheet material.
Advertising and other information is often temporarily presented on large sheets which are placed on billboards, truck panels and the like. One form of such sheet material is tensioned vinyl sheet. The sheet may be printed upon and surrounded by a more rigid plastic border which is RF welded to the sheet. The border typically includes a large bead, circular in cross section, which operates as a tenon in association with a C-shaped mortise associated with the mounting frame.
Mounting frames may take on a plurality of configurations. Of value is the ability to tension the sheet and to maintain it in a tensioned and wrinkle-free state. Mechanisms have been used which first lock the sheet in place and then apply tension through off center bolts and the like.
A recent system includes a mounting for a sheet that has a bead about its periphery. The system includes frame members forming a rectangle with each frame member having mutually parallel multiple engagement surfaces defined on ribs. As one utility, the frame has been mounted on the sides of trucks for advertising. The system further includes elongate retainers having elongate flanges with interlocking surfaces that can selectively interlock with one of the engagement surfaces on the frame members and retainer mortise elements to receive the tenon beads on the periphery of the sheet. The frame also has frame rails having rail surfaces that face away from corresponding retainer rail surfaces on the rails of the retainers. A tool including pinch rollers squeezes the corresponding rail surfaces toward one another to place the sheet material held by the retainer in tension while the interlocking surface is engaged with the appropriate engagement surface. This system is illustrated in U.S. Pat. Nos. 6,276,082 and 6,513,272, the disclosures of which are incorporated herein by reference.
The foregoing panels have found substantial utility in presenting printed indicia for identification and advertising. Further, the systems provide a covering for the sides of trucks which have become unsightly or included no longer appropriated printed indicia. As disclosed, the foregoing systems do not accommodate a surface which is subjected to dimensional change. Rear doors of many trucks are of the roll-up type which include a plurality of elongate panels with articulation therebetween. As the door is raised, the surface element height on the surface of the door increases as the panels transition from a vertical to a horizontal position. As such the surface element length of the door perpendicular to the elongate panels can increase by one-half to two inches while in transition between open and closed.